The present invention relates to a cassette case for a magnetic tape (hereinafter referred to as the cassette case) which contains a magnetic tape therein.
As known, in use of a cassette tape recorder, a problem arises in maintaining the perpendicularity of the magnetic tape in the cassette case, that is, a cassette tape, to the magnetic heads of the cassette tape recorder.
This perpendicularity is not a problem when recording and reproducing a special cassette tape by a so-called two-head type tape recorder which has an erasing head and a recording/reproducing head. However, when using a three-head type tape recorder which is provided with independent magnetic heads for erasing, recording and reproducing, there will be caused an error in the perpendicularity to the recording head and reproducing head since the perpendicularity of the guide part in the cassette case is sometimes in error even when the same type tape recorder is used, and it is necessary to correct the perpendicularity of the cassette tape with respect to these two heads. Even when using a two-head type tape recorder, if the recording and reproduction are carried out by two different units of the same tape recorder, perpendicularity may be in error due to a dimensional error in positioning the cassette case in the respective tape recorders and a difference in the running positions of the tapes in respective tape recorders and therefore phase deviation between right and left channels and deterioration of frequency response will be caused.
For this reason, the conventional cassette tape recorders, particularly three-head type recorders, are provided with an adjusting mechanism which displaces the recording head by an external operation so that the perpendicularity of the recording head can be adjusted relative to the reproducing head.
However, such adjusting mechanism is inconvenient in that the perpendicularity must be adjusted each time the cassette tape is used since the adjusting mechanism actuates only the recording head whereas the perpendicularity of the cassette tape relative to the reproducing head differs individually according to the tape recorder.
Moreover, since the cassette tapes which are currently used have two recording tracks A and B and adjustment of the perpendicularity for track A is ineffective for track B and, the perpendicularity must be adjusted before use of the track B when using the track B after use of the track A. Therefore, the conventional cassette tapes are disadvantageous in that a long interruption is unavoidable in such operation as continuous recording on successive tracks A and B.